A couple of notes before you set up a Quickbooks integration via Zapier:
You will need to have Zapier's base paid plan ($20/mo) to have access to use Quickbooks on Zapier. Sisu is available for free plan members, however, Quickbooks is not.
You will want to make sure that only relevant expenses are sent into Sisu. These are usually monthly recurring expenses such as rent or wages, or general expenses such as dinners/other general business expenses. This would not be something like a transaction fee or a referral paid that would be tracked transactionally in Sisu using the commission form.
These expenses will be pulled into your income report to help give you a good idea of net income.
If you want to set up a filter step so that only some of your expenses pull into Sisu (and not all of them) there are instructions for that here.
And here are the instructions on how to set up a general Quickbooks to Sisu integration: